Simple tiny CMS

No I'm not one of those who need Wordpress or other CMS', I'm quiet knowledgeable about CMS already.

I'm a looking for a kind of "CMS" that uses .html (no PHP) and stores data in XML or TXT format.

it's for a small offline knowledge gather.
basically a search field, where the user can enter a number.
Javascript dynamically returns text and images based on the input.

The user can edit and add information, which in return is stored in said TXT or XML files.

it's important it's no-PHP and no-ASP, since it's going to be running of a non-webserver.
i looked at the new filesystem api, but can't find any good boilerplates or somewhere to get me started, and not too keen on starting it up from scratch.

any of you guys who have seen something like this ?